1. Field of the Invention
The present invention relates to a car power source apparatus that has many batteries connected in series to increase output voltage.
2. Description of the Related Art
To increase output, the car power source apparatus increases voltage by having many batteries connected in series. In this power source apparatus, all the series connected batteries are charged by the same charging current, and all batteries are discharged by the same current as well. As a result, if all batteries have exactly the same characteristics, no battery voltage or remaining capacity imbalance will develop between batteries. However, in actuality, batteries with exactly the same characteristics cannot be manufactured. When charging and discharging is performed repeatedly, an imbalance in voltage or remaining capacity develops between batteries. Furthermore, battery voltage imbalance can be the cause of over-charging or over-discharging of a particular battery. To prevent this detrimental effect, a car power source apparatus that detects the voltage of each battery and eliminates any imbalance has been developed (Japanese Patent Application Disclosure 2004-7915).